1)
What is "Lefanim"?
1.
Rashi: It is before.
2)
Why does it say "Lefanim ha'Aretz Yasadta"?
1.
Radak: The previous verse said that You exist forever, without end; here it teaches that You are first, without beginning. You made Shamayim and Eretz, unlike those who say that the world is Kadmon (always existed). Rather, You created it.
2.
Malbim: The land is like the foundation of a building; Shamayim is like a building above. This includes the entire tangible world that is subject to time.
